feat: orchestrate on-demand runtime residency

[schickling-assistant]

Problem

The residency model and provider resume capabilities need one host-owned policy that decides when to go cold, completes safe teardown, and wakes without weakening message delivery semantics.

Goal

Orchestrate on-demand residency with explicit host policy, durable demand, complete-group teardown, exact launch-attempt fencing, and user-facing wake commands.

Decisions

• Configure one host idle threshold and warm capacity; no policy means on-demand launches are suppressed.
• Wake only from durable unread inbox work, st2 wake, or st2 pty attach <agent>.
• Once checkpointing starts, finish stop and verify complete absence before servicing racing demand.
• Mint an independent host launch-attempt incarnation. Rotate it when the canonical provider is absent; retain it while that provider is live and sidecars converge.
• Require Codex, OMP, and Claude readiness to match both generation and the exact host attempt incarnation.
• Emit timestamped transition events, but define no latency SLO before a live canary is measured.

Verification

• cargo check --workspace
• cargo test --lib residency_host::tests -- --nocapture — 6 passed.
• Full OMP module — 18 passed.
• Full Claude module — 29 passed before cleanup; exact launch-attempt readiness passes after cleanup.
• Provider observer tests — 3 passed.
• No-policy launch suppression test passes.
• CLI help exposes wake; Clap rejects a generation fence without its paired incarnation.
• Final review found no correctness findings.

Complexity

The host coordinator is deliberately explicit about every durable boundary: demand observation, checkpoint, full-group stop, verified absence, resume preparation, launch attempt, and provider readiness.

Concerns

The workspace suite reports eight pre-existing Darwin path/resync failures. A representative resync failure reproduces unchanged on the parent branch. The Codex module also has the known parallel lock race tracked by PR #318.

Friction & bottlenecks

cargo fmt --check reports broad pre-existing formatting drift, so this stack avoids a repo-wide formatting rewrite. This repository has no devenv quick-check task.

Follow-ups

• Add one downstream host canary configuration and deploy only with explicit operator approval.
• Measure cold-to-ready latency and resident resource reduction before setting an SLO.

References

Depends on PR #493. Part of stack #495. Related test deflake: PR #318.

Posted on behalf of @schickling

field	value
agent_identity	mbp2025.direct.omp.bn5hrz39
session	mbp2025.bn5hrz39
agent_persona	generalist
agent_supervisor	unavailable
agent_tool	OMP
agent_tool_version	18.1.7
agent_runtime	OMP 18.1.7
tooling_profile	dotfiles@4816a7a